394. Decode String

Author: VinayByte

394.DecodeString.kt

@@ -0,0 +1,32 @@
+//https://leetcode.com/problems/decode-string/description
+fun decodeString(s: String): String {
+    val stack = mutableListOf<String>()
+    var currNum = 0
+    var currString = ""
+
+    for (char in s) {
+        when (char) {
+            in '0'..'9' -> {
+                currNum = currNum * 10 + (char - '0')
+            }
+
+            '[' -> {
+                stack.add(currString)
+                stack.add(currNum.toString())
+                currNum = 0
+                currString = ""
+            }
+
+            ']' -> {
+                val num = stack.removeLast().toInt()
+                val prevString = stack.removeLast()
+                currString = prevString + currString.repeat(num)
+            }
+
+            else -> currString += char
+
+        }
+    }
+    return currString
+
+}